5. DIFFERENCES ALIGN
The crux of the explanation is as follows:
According to Rambam, there is no way for there to be a “presumed status” regarding a minor’s level of knowledge. This is because a “presumed status” only applies when something is solid and fixed, and will certainly remain this way. However, it’s impossible for there to be any assurances when it comes to a minor’s intellect, because a minor doesn’t (truly) have knowledge. One of the qualities of (a person who has) knowledge is that once one makes an intellectual resolution and decision, it doesn’t change. Minors, as can be clearly seen, are constantly changing, and it is impossible for them to make a steadfast resolution. Their decisions can easily be changed or adjusted.
[As per the well-known explanation of why a minor under the age of thirteen, even one who is “sharp, intelligent, has a good grasp, and is proficient and fluent in the laws of all the positive and negative commandments,” is nonetheless not punished for transgressing a mitzvah — due to his lack of knowledge].
This is why Rambam rules halachically, “We do not say: ‘Since they were knowledgeable at the beginning of the year, they no longer have to be examined.’ Instead, we examine them throughout the entire year.” To Rambam, it is very obvious reasoning (to which everyone would agree) that there can be no “presumed status” in such a case.
In light of this understanding, the difference between the two versions of the Gemara — “and did not know how to utter a vow” or “and knew how to utter a vow” — is as follows:
The version of “It might enter your mind to say... {in a case} where we examine her for thirty {days after she turned eleven} and she did not know how to utter a vow properly, {one might} say that one should examine her no further” aligns with the opinion that “the age of vows” is “the twelfth year for a female minor and the thirteenth year for a male minor” (when they know for Whose sake they are vowing). This is because according to this opinion {that “the age of vows” begins at age eleven and one day for females and twelve and one day for males}, there is a greater novelty in this rule {that if she failed an examination, she is nevertheless examined again the next time she vows} than in the ruling (of Rambam) cited above that “we examine them the entire year” even though “they were knowledgeable at the beginning of the year” (as will be explained below, Section 8).
However, according to the opinion that “the age of vows” is “after a female minor turns twelve or a male minor turns thirteen” (as Rambam indeed concludes), there is no logical reason to assume that she wouldn’t need to be examined again when “we examine her... and she did not know how to utter a vow properly.” Because of this, Rambam must adopt the unconventional version of “It might enter your mind to say... ‘{in a case} where we examine her... and she knew how to utter a vow properly” (as will be explained below, Section 8).
